The effect of association of rye and Austrian winter peas and of nitrate of soda on nitrogen fixation

Austrian winter peas and rye were grown separately and together in the greenhouse in 3-gallon pots. Nitrate of soda was applied at the rates of 0, 50, 100, 200, 400, and 800 pounds per acre. The yield and nitrogen content of the tops and roots were determined. The following conclusions were drawn: The application of nitrate of soda in large amounts reduced the yield and nitrogen content of Austrian winter peas when grown alone and when grown with rye. The application of nitrate of soda increased the yield and nitrogen content of the rye in proportion to the amount of nitrate of soda applied. The yield of Austrian winter pea tops was reduced slightly by the growth of rye with the peas. The yield of rye grown with Austrian winter peas was almost as large as that of rye grown alone when small amounts of nitrate of soda were applied and considerably less when high amounts of nitrate of soda were applied. The combined yield of Austrian winter peas and rye grown together was considerably greater than that of Austrian winter peas grown alone. The percentage of nitrogen in the combined Austrian winter peas and rye grown together was not significantly less than that of Austrian winter peas grown alone. The growth of rye with Austrian winter peas increased the average nitrogen content of the peas from 2.39 to 2.74%. The growth of Austrian winter peas with rye increased the average nitrogen content of the rye from 0.94 to 1.35%. The total nitrogen in the Austrian winter peas and rye was 0.33 gram per pot greater than where peas were grown alone. The application of nitrate of soda reduced the nitrogen fixed where Austrian winter peas, Austrian winter peas and rye, and rye were grown. The growth of rye with Austrian winter peas increased the nitrogen fixed from 1.44 grams per pot where peas were grown alone to 1.77 grams per pot where they were grown together. The rye and the Austrian winter pea tops each contained practically the same quantity of nitrogen when grown together as each had when grown separately. The growth of rye with Austrian winter peas increased the nitrogen fixed by an amount almost as large as the quantity of nitrogen in the rye, i. e., 0.33 and 0.37 gram per pot, respectively.